Hi All, giving the 03 sy a once over, I found that there is alot of travel in the clutch arm before I would feel the pushrod connecting with the clutch plate, I have removed the ball bearing and pushrod and there seems to be enough wear on the pushrod ends, does anyone know what the actual spec for the length of the pushrod? Is it shared with any other yamy' engines?

 

When you say there is a lot of clutch arm travel before it starts to work, that is normal for motors with a rotating cam clutch mechanism like yours.

The important thing about pushrod length is that the angle between the clutch arm and the slave cylinder is about 90 degrees at the point when the pushrod starts pushing against the pressure plate.

The SY250 does have a falrly easily-bent clutch arm. The original design on that motor when it was in the TY250Z was for a cable clutch. The hydraulic clutch setup was designed for when Yamaha started selling the motors to Scorpa for the SY250. The location of the exhaust chamber on the SY250 dictated a compromise shape for the clutch lever.

To answer your pushrod question, most likely the pushrod is the same as what's in an early 1990s YZ250, because that's what the TY250Z motor was developed from. You could check this using part number cross-referencing.

Thanks for the info, from the time I acquired the bike, the adjustment on the clutch arm was pretty much bottomed out, as in the threaded adjuster was almost flush with the lock nut, and I would say that there is approximately 12mm of clutch arm rotation before it engages the push rod, the angles are ok, yes the clutch arm pivot is easily bent, everything lines up well for proper slave to clutch arm function, my thoughts were that if the adjustment was maxed that there is wear that could be addressed and rectified, as I'm sure from the factory they wouldn't have been "cranked" in so far? I will look into the older yz parts to see if I cam locate one or at least the o.e. specs on it, cheers!